Apparatus for determining air conditions



My 18, 1939. a. v. WOODLING 2,165,697

APPARATUS FOR DETERMINING AIR CONDITIONS Original Filed April 22, 1932'5 Sheets-Sheet l PSY RIC WIT FFECTIVE TEM ERATURE LINES FOR STILL AICONDITIONS RSONS NORM LLY CLOTHED .5 AND SLIGHTLY ACTIVE 2. A. 5. H. V.E. 3: Research Lubororory U.5 Bureau of Mines g PITI'JbUTQH, Po. O

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Grains ofmo'lsfure per pnund of dry air: 02

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80 30 I00 Dry bu I b Temperature HO I20 I30 INVENTOR y 71939. e. v.WOODLIN G APPARATUS FOR DETERMINING AIR CONDITIONS 5 Sheets-Sheet 2Original Filed April 22, 1932 L mayo 80 7o Di ff'eren fia/ TemperafureScale Dry Bu/b- We) Bulb We? Bulb Temperafure Sea/e Effecfil/eTempera/ure Scale 0/ f feren f/a/ Temperafures Dry Bulb TerhperafureScale Jul 18, 1939. a.v.wooo1 me APPARATUS FOR DETERMINING AIRCONDITIONS Original Filed April 22, 1932 5 Sheets-Sheet 3 Wef Bulb DryBu/ Anmomefer 55 7" SO 'D B J5DiffeIenf- 653 I 01; ffenhal I20 0 8 INVENTOR July 18, 1939. G v WOQDLING 2,166,697

APPARATUS FOR DETERMINING AIR CONDITIONS Original Filed ApIil 22, 1932 5Sheets-Sheet 4 /one only/1+ firaph-Member 5'0 so a?! E ffec five Temp.G'mph Member Values for fhe lllusfrafea Posifions.

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Zr We? Bulb Tempera'fure 72 3. Differenfia/ Temperafure l8 INVENTOR 5.Effecfive Emperafure Patented July 18, 1939 UNITED STATES PATENT OFFICEAPPARATUS FOR DETERMINING AIR CONDITIONS George V. Woodling, Cleveland,Ohio, assignor to General Motors Corporation, a

of Delaware corporation 34 Claims.

My invention relates, in general, to air conditioning, and moreparticularly to' means for measuring the condition of the air.

This application is a division of my pending application for LettersPatent, Serial Number 606,837, filed April 22, 1932, entitled Measuringand regulating devices, and which issued into Patent No. 2,139,295, Dec.6, 1938.

An object of my invention is to provide for measuring the relativehumidity and the effective temperature of air.

Another object of my invention is to give a measurement that is a trueindex of a persons feeling of comfort or discomfort in all combinationsof the dry bulb temperature, the relative humidity and the air velocity.

A further object of my invention. is to translate three movements into asingle resultant movement.

A still further object of my invention is the provision of apsychrometric device that measures the effective temperature in allcombinations of the dry bulb temperature, the relative humidity, and theair velocity.

Another object of my invention is the provision of a psychrometricdevice that is responsive to the dry and wet bulb temperatures formeasuring the relative humidity. v

Other objects and a fuller understanding of my invention may be had byreferring to the following descriptions, taken in connection with theaccompanying drawings, in which:

Fig. 1 is a psychrometric chart with effective temperature lines forstill air conditions, persons normally clothed and slightly active,

Fig. 2 is a psychrometric chart with effective temperature lines for anair velocity of 300 feet per minute, persons normally clothed andslightly active,

Fig. 3 is the graphical representation of a method for determining therelative humidity from the dry bulb and wet bulb temperatures.

Fig. 4 is the graphical representation of a method for determining theeffective temperature for all combinations of dry ,bulb temperatures,wet bulb temperatures, and air velocities.

Fig. 5 is a graph showing the relationship between the lineardisplacement plotted against the numerical values, as marked off on theline CD of Fig. 4,

Fig. 6 is a graph showing the relationship between the lineardisplacement plotted against the numerical values, as marked oil on theline EF of Fi 4,

Fig. 'l is a plan view of a psychrometric device that measures both therelative humidity for all combinations of dry and wet bulb temperatures,and the efiective temperature for all combinations of the dry and wetbulb temperatures, together with the air velocities,

Fig. Bis a rear elevational view of the psychrometric device, shown inFig. 7,

Fig. 9 is a view taken along the lines a-b of Fig. 7, part of theelements being omitted to clarify the view, as well as to explain therelative angular displacements of the various parts,

Fig. 10 is a front elevational view of the psychrometric device shown inFig. '7, and illustrates indicating hands for the dry bulb temperature,the wet bulb temperatures, the effective temperature, and the relativehumidity, together with graph-members based upon the efiectivetemperature and the relative humidity,

Fig. 11 is a diagrammatic view of two fundamental circuits that may beassociated with two psychrometric devices for regulating the effectivetemperature of the air inside of a building in accordance with theeffective temperature of the air surrounding the building,

Fig. 12 is a graph, together with a chart upon which it is based,showing the desirable inside effective temperatures as compared to theoutside effective temperatures,

Fig. 13 is a fundamental circuit that may be associated with thepsychrometric device for regulating the relative humidity of a buildingor enclosure at any predetermined selected value,

Fig. 14 is a modified form of the circuit shown in Fig. 13, and employsgrid-controlled glow-discharge tubes for operating the air conditioningequipment,

Fig. 15 is a fragmentary showing of a control system wherein theelectro-magnets that operate the air conditioning equipment may beoperated by a control circuit employing grid-controlled glow-dischargetubes, such as the circuit shown in Fig. 14, and

Fig. 16 is a diagrammatic View showing conventional air conditioningapparatus which may be controlled by the control system shown in Fig.11.

The effective temperature is anexperimentally determined scale, andtherefore represents the true index of a person's feeling of warmth inall combinations of temperature, humidity, and air motion.

The temperature sensations of the human body depend not only upon thetemperature of the surrounding air as registered by a dry-bulbthermometer, but also upon the temperature as indicated by the wet-bulbthermometer, together with the air motion. Human comfort or discomfort,as regards feeling of warmth, depends largely upon the body temperature,and, therefore, upon the relation between the rate of production anddissipation of heat.

By the process of metabolism heat is constantly generated within thebody, which heat must be eliminated from the surface of the body andfrom the respiratory tract by radiation, convection and evaporation.Hence, to maintain a constant body temperature the heat loss must equalthe heat produced. It is, therefore, apparent that any reduction in theelimination of heat from the body must result in a rise in temperatureand a corresponding feeling of discomfort. As the temperature of the airand surrounding objects rise, the loss of heat by convection andradiation decreases. When the air temperature reaches that of the body,the loss by radiation and convection ceases. Finally, as the airtemperature exceeds tl" at of the body, heat is transferred from the airto the body. As the temperature of the air rises and heat loss byradiation and convection decreases, the body endeavors to maintaintemperature equilibrium by making available more perspiration, thusresulting in a greater heat loss by evaporation.

From the foregoing, one notes that there must necessarily exist certaincombinations of air temperatures, air humidities and air motions, whichproduce the same total heat loss from a person by radiation, convection,and evaporation which produce the same feeling of comfort or discomfortupon the person notwithstanding variations in one or more components ofsaid combinations.

The combinations of temperature, humidity and air movement which producethe same feeling of warmth are called thermo-equivalent conditions oreffective temperature lines. Elaborate experiments show that thisnewly-developed scale of thermo-equivalent conditions not only indicatesthe sensation of warmth, but also determines the physiological effectson the body induced by heat and cold. For this reason, thethermo-equivalent condition is generally referred to as the effectivetemperature scale or index.

Effective temperature is an experimentally determined scale which unlikethe dry-bulb and wet-bulb scales is a true measure or index of a personsfeeling of warmth in all combinations of temperature, humidity, and airmovements. In other words, for any one given effective temperature aperson feels the same degree of warmth or coldness regardless of thedry-bulb temperature, the wet-bulb temperature, and velocity of the airrequired to produce that particular effective temperature.

With reference to the two psychrometrio charts of Figs. 1 and 2, the drybulb temperature is plotted as abscissae and the grains of moisture perpound of dry air as ordinates. The maximum moisture which the air canhold at various temperatures gives the saturation, or 100 percentrelative humidity curve. Relative humiditiesbetween zero and 100 percentare given by a series of curved lines similar to the saturation curve.

. The wet bulb temperatures for all atmospheric conditions are given bya series of nearly parallel oblique lines. Effective temperature isgiven by e a series of oblique but not parallel lines which approachbeing parallel to the wet-bulb lines at bulb temperature line at 46. InFig. 2, which is for air moving at the rate of 300 feet per minute, theeffective temperature line is vertical and coincides with the dry-bulbtemperature line at 56. Although not shown, for air velocities of 100and 500 feet per minute the effective temperature lines and the dry-bulbtemperature lines coincide respectively at 51 and 59.

For dry-bulb temperatures below these respective values, an increase inhumidity produces a cooler sensation, instead of a warmer sensation asis produced for dry-bulb temperatures above these values. The values maybe called the dividing lines at which humidity has no effect upon thecomfort of the body.

The psychrometric chart of Fig. 2 for moving air, differs from the shartof Fig. 1 for still air only in that the effective temperature lines forany particular degree do not intersect the drybulb, and wet-bulbtemperature lines at the same degree on the saturation or 100 percentrelative humidity curve, but are removed to the right so that theeffective temperature for any dry and wet bulb temperature is lower formoving air than it is for still air. This difference between theeffective temperature for still airand for moving air, of any velocity,is the cooling resulting from that velocity.

Referring to the psychrometric chart in Fig. 1, a dry-bulb temperatureof 70 and a wet-bulb temperature of 54 produces an effective temperatureof 65". This is for still air. Referring to Fig. 2, which is for airmoving at the rate of 300 feet per minute, the same dry and wet bulbtemperatures produces an effective temperature of 60, or a reduction ofresulting from a change in air velocity.

For winter-time conditions in relatively cold climates, and for personsnormally clothed and slightly active, extensive tests show that thecomfort zone ranges from an effective temperature of 62 F. to aneifective temperature of 69 F. That particular eflective temperature atwhich a maximum number of people feel comfortable is called the comfortline.v While at rest, 97 percent of the people have been found to becomfortable at an effective temperature of 64 F., and this temperatureis generally considered as the winter comfort line or optimum effectivetemperature. However, persons working at various rates are mostcomfortable at effective temperatures below 64 F. The foregoingdiscussion respecting the effective temperature is merely a briefrestatement of the subject matter published in the Transactions of theAmerican Society of Heating and Ventilating Engineers from 1923 to thepresent date by F. C. Haughten and C. P. Yaglou.

Since one of the purposes of the psychrometric device is to measure theeffective temperature,

it follows that its functioning must be based upon a useful andpractical relationship that combines the dry bulb temperature, therelative humidity, and the air motion. From a study of the psychrometriccharts of Figs. 1 and 2, together with other psychrometric charts (notshown), I find that by reorganizing the foregoing values upon adifferent basis, a useful and practical relation results. Such arelationship is shown in Fig. 4. In this relationship, however, therelative humidity is not considered directly, but by its derived value,as determined by the dry bulb and wet bulb readings.

In Fig. 4, the dry bulb'temperature is scaled amount to be subtractedfrom the dry bulb temperature to equal the effective temperature iszero. This establishes the zero point on the line EF. Similarly, withreference to the psychrometric chart of Fig. 2, which is for an airvelocity of 300 feet per minute, one observes that, at a dry bulbtemperature of 56, the amount to be subtracted from the dry bulbtemperature to equal the effective temperature is This establishes thepoint 300 on the line EF. The points for air velocities of 100, 200, 400and 500 may be established in a similar manner.

The line CD is likewise empirically established by first plotting afamily of lines which have for their base the line EF and which convergeat a dry bulb temperature of 120 F. The values for plotting the familyof lines are obtainedfrom the psychrometric charts of Figs. 1 and 2,together with other similar charts (not shown). For instance, the lineG, interconnecting the zero point on the line EF and the point on theline CD is determined by establishing a series of points, the values ofwhich being obtained from the psychrometric chart of Fig. 1, and drawinga line through the said points. With reference to Fig. 1, which is forstill air, we observe that, at a dry bulb temperature of 75 F. and a wetbulb temperature of 70 F., (a difference of 5), the effectivetemperature is 723 F. This means that, at a dry bulb temperature of 75F. and with a difference of 5 between the dry bulb and the wet bulbtemperatures, the amount to be subtracted from the dry bulb temperatureto equal the corresponding effective temperature, is 2.3". Therefore,with reference to Fig. 4, a dry bulb temperature of 75 F., as measuredon the line CY, and a value of 2.3, as measured on the line OX,established a point h for the line G. For the point on the line G, weobserve from Fig. 1 that the amount to be subtracted from a dry bulbtemperature of 100 F., (with a wet bulb temperature of 95 F.) to equalthe corresponding effective temperature, is 4. Similarly, for the point5, being the point where the line G intersects the line CD, we observefrom Fig. 1 that the amount to be subtracted from a dry bulb temperatureof 120 F., (with a wet bulb temperature of 115 F.), to equal thecorresponding effective temperature, is 5.5".

Other points for establishing the position of the line, G, may bedetermined in the same manner. As will be noted, the established pointsfor the line, G, lie in a straight line.

The other l nes interconnecting the zero point on the line EF and thepoints I 0, 20 and 30 on the line CD may be established in the samemanner as the line, G, was established, except that the differencesbetween the dry bulb temperatures and the wet bulb temperatures are 10,20 and 30, respectively. A

The family of lines interconnecting the point 300 on the line EF and thepoints 5, l0 and 20 on the line CD may also be established in a similarmanner, except that the values for establishing these lines are takenfrom the psychrometric chartin Fig. 2, which is for an air velocity of300 feet per minute. The values for determining the family of linesinterconnecting the points )0 and 500 on the line EF and the points 5,l0 and 20 on the line CD are taken from psychrometric charts (not shown)for air velocities of 100 and 500 feet per minute, respectively. As willbe observed, all of these lines are substantially straight, except thosefor the higher air velocities, and they may, for all practical purposes,be considered straight. While I have drawn the foregoing family of linesto explain the method as to how they are established, it is readilyapparent that an infinite number of such lines may be drawn. From thereorganized psychrometric chart of Fig. 4, one observes that the familyof lines converge at 120 F., thus indicating-that at this hightemperature the air velocity has no cooling effect upon the body.Therefore, when the chart in Fig. 4 is once established, we can obtainfrom it the amount to be subtracted from the dry bulb temperature toequal the corresponding effective temperature for all possiblecombinations of dry bulb temperature, wet bulb temperatures and airvelocities. As will appear later, that part of the psychrometric devicefor measuring the effective temperature is based upon the chart of Fig.4. However, before describ ng the structural features of thepsychrometric device, I will explain the basis for directly determiningthe relative humidity from the dry bulb and wet bulb temperaturereadings.

With reference to the-chart in Fig. 3, the dry bulb temperature readingsare sealed off on the arcuate line JK; the difference between the dry bub and the wet bulb temperatures on the arcuate line 1M; and the relativehumidity on the straight horizontal line LN. The angular position of thearcuate line LM relative to the arcuate line JK is determined by makingthe zero or starting point of the line LM and the dry bulb temperaturereading of 60 on the line JK lie on the same radius; namely, the lineOPL. The radial position of the arcuate line JK relative to the arcuateline LM is such that the distance OP equals two-thirds of the radialdistance 0L. However, any other ratio may be employed so long as theproper considerations of all the factors effecting the ratio are takeninto account. As illustrated, the dry bulb temperature readings, asmarked off on the arcuate line JK, range from 46 to 120 F., and thedifferential readings, as marked off on the arcuate line LM, range from0 to 35. These temperature readings correspond to those shown in Fig. 4,and are more than adequate to accommodate any and all possible heatingand air conditioning requirements. The relative arcuate lengths of thedry bulb temperature scale JK and the differential scale LM may bearsubstantially the same proportion as shown. However, should it bedesirable to reduce the length of the relative humidity scale LN, thismay be done by reducing the arcuate length of the differential scale LMrelative to the arcuate length of the dry bulb temperature scale JK.Both the position and the readings, as marked off on the relativehumidity line LN, are established empirically by drawing intersectinglines through the dry bulb temperature scale JK and the difierentialscale LM. Referring again to the psychrometric chart of Fig. 1, weobserve that a dry bulb temperature of 70 and a wet bulb temperature of59 (a diiferenceof 11) give a relative humidity of 50 percent, and thata dry bub temperature of 100 and a wet bulb temperature of 84 (adifference of 16) likewise give a relative humidity of 50 percent.Hence, the

intersection of a line drawn through 70 on the 475 scale JK and 11 onthe scale LM with aline drawn through 100 0n the line JK and 16 on thescale LM determines the point for percent relative humidity. Similarly,the intersection of a line drawn'through a on the scale JK and 14 on thescale LM with a line drawn through 100 on the scale JK and 20.5 on thescale LM determines the point for 40 percent relative humidity. Asillustrated, other points for the relative humidity line LN may bedetermined in a similar manner. I find that, by plotting the chart shownin Fig. 3 on a large scale the working range of the relative humidityscale LN is very accurate. However, there is a slight percentage oferror at the extreme ends of the scale.

That part of the psychrometric device for measuring the relativehumidity is based upon the charts in Figs. 3 and 4. As far as it ispossible to do so, the two parts will be described separately, eventhough structurally they are mutually dependent. I will describe thepart concerning the relative humidity first.

With particular reference to Figs. 7, 8, 9 and 10, the referencecharacters 500 and 50| represent two rotatable shafts, the rotation ofwhich are, respectively, responsive to the dry and wet bulbtemperatures. Several methods, well known in the art, are availableforoperating the dry and wet temperature shafts, but, since thisconstitutes no part of my invention, I have omitted making a showing ofsuch a means. Generally, such a means may comprise a tube containing athermoexpansive fluid connected to a Bourdon tube helix which expandsand unwinds in a well known manner to rotate the said shafts. For thedry bulb temperature shaft 500, the tube that contains thethermo-expansive fluid is exposed to the ordinary atmosphere and for thewet bulb temperature shaft 50|, the tube may be either surrounded with awick dipped into a tank of water or any other means to effect anevaporation. Also, as a modification, the dry and wet bulb shafts 500and SM may be remotely controlled by an electrical means that isresponsve to a dry and a wet bulb thermometer.

As ilustrated, the dry and wet bulb temperature shafts are rotativelymounted in brackets 50!. which are supported by a base member 503.Through a transmission of the planetary type, the two shafts arearranged to operate a dry bulb temperature hand 505 and a differentialtemperature hand 506. As shown in Fig. 10, the dry bulbtemperature'scale JK, the differential temperature scale LM, and therelative humidity scale LN provided upon the face 509 of thepsychrometric device are constructed upon the same basis as the chartshown in Fig. 3. The effective temperature hand is represented by thereference character 50! and the wet bulb temperature hand by 508. Theirvalues are read off on the dry bulb temperature scale JK.

The dry bulb temperature shaft 500 extends through the various parts ofthe psychrometric device and the dry bulb temperature hand 505 isconnected upon the outer or right-hand end thereof. Surrounding the drybulb temperature shaft 500 is a hollow or tubular shaft H0, and thedifferential temperature hand 506 is connected to the outer orright-hand end thereof and the rear or left-hand end thereof isconnected to the differential transmission. Inasmuch as the lineararcuate unit for the differential scale LM is larger than thecorresponding arcuate linear unit for the dry bulb temperature scale JK,the left-hand end of the tubular shaft H0 is connected to the sun gear 5and the dry bulb temperature shaft 500 is connected through the usualspider to the planetary gears 5|3 of the differential transmission. Theorbit gear 5" of the transmission is driven by the wet bulb temperatureshaft 50| through a gear wheel 5|5. In this manner, the difference inangular displacement of the dry and. wet bulb temperature shafts istransmitted through the sun gear 5|2 and hence the tubular shaft 5|0 tothe diiferential hand 506. The gear wheels of the planetary transmissionare so proportioned that, for any reading of the dry and the wet bulbtemperature hands 505 and 508, as marked off on the scale JK, thedifferential hand 506 indicates a value, as marked of! on thedifferential scale LM, that is the difference between the dry and wetbulb temperature readings.

As illustrated, the relative humidity scale LN may be horizontallysupported upon the face 509 by suitable pins 5|5 or their equivalents.The lower edge of the relative humidity scale is provided with alongitudinal slot in which a pin 5|! is disposed to be slidably mounted.Interconnecting the pin 5|! and the outer ends of the dry bulbtemperature hand 505 and the differential temperature hand 506 is aslottedarm 5| 8. Hence, as the dry bulb temperature hand 505 and thedifferential temperature hand assumes different relative positions, theupper end of the slotted arm- 5l8 constrains the pin 5|"! to move alongthe longitudinal slot of the relative humidity scale LN. The position ofthe pin 5|! determines the relative humidity reading for thecorresponding readings of the dry and wet bulb temperatures.

In the position as shown, the dry bulb temperature hand 505 indicates atemperature of upon the scale JK and the differential temperature of 18.For this position of the dry bulb temperature hand 505 and thedifferential hand 500, the corresponding relative humidity reading is 40percent. This particular setting of the hands is also indicated on thechart shown in Fig. 3. The heavy line 505 represents the position of thedry bulb temperature hand 505; the heavy line 505 indicates the positionof the differential hand 500 and the heavy line 5|8 indicates theslotted arm 5|0. As is readily apparent, my psychrometric deviceprovides for measuring the relative humidity for any and all possiblecombinations of dry bulb and wet bulb temperatures.

For the purpose of regulating the humidifying equipment of an airconditioning system, I pro vide a relative humidity graph-member 520 anda light projector I I2 (see Figs. 10 and 13) for varying the'amount oflight falling upon a photo-electric cell 0 of an amplifying circuit,which, in turn, actuates a pole changer relay 525 for controlling thepolarity of the current delivered to the humidifying equipment. Theamplifying circuit and the light projector l 2 for accomplishing this 1result are shown in Fig. 13.

Two well known methods are available for varying the amount of lightthat passes through the light transmitting portion l H of thegraph-member 520. One may be termed the linear meth- 0d, and the otherthe area method. With reference to the light projector M2, the linearmethodmay be described as follows: The light projector H2 comprises, ingeneral, a cylindrical housing I IS in which are disposed, at the leftend, two condensing lenses I20 and, at the right end, two objectivelenses |2|, and, in the middle, a transversely disposed member having avertical narrow slot I22. By means of the condensing lenses I20 and theobjective lenses I2 I, and the slit I22, the light from the concentratedfilament of the lamp I I I is formed into a plane of light. Theintensity of this plane of light may be suitably varied by' theadjustable resistor I45 that is connected in circuit relation with thesource of electrical energy I42.

As shown, this plane of light is directed perpendicularly to the planeof the transversely disposed relative humidity graph-member 520. Byreason of the demagnifying efiect of the lenses the width of the planeof light at its focal point, being the point at which it passes throughthe light transmitting portion H4, is several times smaller than thewidth of the slit I22. The breadth or the height of the plane of lightis slightlygreater than the maximum height of the light transmittingportion II4. Therefore, the quantity of light falling upon thephoto-electric cell H is determined by the amount that the graph-member520 is transversely moved relatively to the plane of light, or, in otherwords, by the height of the ordinate of the light transmitting portionH4.

The graph-member 520, may be constructed either of a thin sheet ofopaque material or of a photographic film. When the graph-member 520 isconstructed of a thin sheet of opaque material, the light transmittingportion I I4 takes the form of an aperture, but when a photographic filmis used, the light transmitting portion H4 is transparent while thesurrounding portion is dark. In the case of a photographic film it isessential that the degree of transparency be uniform throughout thelight transmitting portion II4. By utilizing a photographic film, thegraph-member may be plotted on an enlarged scale and reduced to a sizeapplicable for the photo-electric cell 'by taking a reduced photographof the enlarged graph-member. This makes a very accurate and convenientmethod of making graph-members. As is apparent, the maximum, height ofthe light transmitting portions of the graph-members must not exceed theillumination boundaries of a photoelectric cell. 1

The relative humidity graph-member 520 is connected to the upper endofthe slotted arm I8 and may be slidably mounted in any suitable mannerwith reference to the light source I I I and the photo-electric cell IIOof the amplifying circult of Fig. 13. With reference to the relativehumidity graph-member 520, the vertical dotted line represents the planeof light. In order to make the showing of the hands of the psychrometricdevice as clear as possible, I have omitted the relative humiditygraph-member 520 in Fig. 7. The base of the light transmitting portionof the relative humidity graph-member 520 is the same length as therelative humidity scale LN and to every relative humidity value, asmarked on on the base of the light transmitting portion therecorresponds an ordinate of the same value. Therefore, the amount oflight falling upon the photo-electric cell H0 is directly proportionalto the readings of the relative humidity.

The photo-electric cell H0 is a light-sensitive device which, whenconnected to a circuit of the proper potential and when illuminated froma suitable source, passes a very small amount of current of the order ofmicro-amperes. The

photo-electric cell H0 comprises, generally, ananode III and a cathodeIl8 sealed within either an evacuated space or within a space filledwith a gas at a very low pressure. The cathode H8 is constructed of amaterial that has the property of liberating electrons when illuminated.By impressing a potential of the proper polarity and magnitude betweenthe anode Ill and the cathode II8, the liberated electrons move towardthe anode I", thus effecting a passage of current in response to thelight falling upon the cathode I I8. Throughout the usual range ofillumination, the current passed by a photo-electric cell is directlyproportional to the illumination.

As is well known in the art, the feeble current that is passed by aphoto-electric cell may, by means of either thermionic amplifiers or bygridcontrolled glow-discharge tubes, be efiectively amplified to operateelectrical meters and sturdy relays. Each type of amplification hascertain distinct advantages over the other.

Under correct and proper operating conditions, the output of athermionic amplifier is directly proportional to the light falling uponthe photoelectric cell, whereas this is not exactly true withgrid-controlled glow-discharge tubes. However, with the proper circuits,a fair degree of Proportionality can be obtained by utilizinggridcontrolled glow-discharge tubes. By reason of the high degree ofproportionality, the combination of the photo-electric cell and thethermionic amplifiers, provides a good light meter and may, therefore,be suitably adapted to give calibrated indications and to operate pilotrelays.

Although there are many amplifying circuits utilizing thermionicamplifiers with either direct or alternating current, or with one ormore stages of amplification, I have preferably illustrated in Fig. 13,a simple direct current thermionic amplifying circuit having only onestage of amplification. However, it is to be understood that I do notintend to limit my invention to the illustrated embodiment.

The illustrated amplifying circuit of Fig. 13 comprises, in general, thethermionic tube II5 having a filament I3I, a grid I32, and a. plate I33,a grid resistor I40, a grid potentiometer I4I for biasing the potentialof the grid I32, relative to the filament I3I, a filament battery I34, aplate battery I35, and a grid potentiometer battery I36. The platebattery I35 and the grid potentiometer battery I36 are. connected inseries circuit relation so that the sum of their voltages, except asmodified by the grid potentiometer MI, is impressed across the anode II1 and the cathode I I8 of the photo-electric cell IIO.

In operation, when no light is falling upon the photo-electric cell IIO,it passes no current, with the result that the grid I32 of thethermionic tube H5 is sufficiently negatively charged with respect tothe filament I3I, as determined by the setting of the grid potentiometer-I4I, that thevalue of the impedance between the plate I33 and thefilament I3I is sufliciently high that very little, if any, platecurrent flows through the thermionic tube II5. However, when thephotoelectric cell H0 is illuminated, it passes a current for decreasingthe impedance of the thermionic tube H5. The current passed by thephoto-electric cell IIO fiows from the positive terminal of the batteryI35 through the winding of the relay 525, the relative humidityrecording meter 525, conductors I5I and I52, the anode III and thecathode II8 of the photo-electric cell, a conductor I53, the gridresistor I40, the grid potentiometer HI, and to the batteries I 35 andI35. The current flowing through the photo-electric cell H0 causes avoltage drop over the grid resistor I40 in such direction as to causethe grid I32 to become less negatively charged with respect to thefilament I3 I, with the result that the impedance of the thermionic tube5 decreases. A decrease in the impedance ofthe thermionic tube 5 allowsa plate current to flow from the positive terminal of the battery I35through the winding of the relay 525, the recording meter 525, the plateI33 and the filament |3| of the thermionic tube, and to the negativeterminal of the battery I35.

The amplifying characteristics of a thermionic tube is linear, except atthe two extreme ends of the grid bias voltage. Therefore, in view of thefact that the responses of the photo-electric cell is also linear, thequantity of current that flows through the plate circuit of thethermionic tube 5 is linear with respect to the amount of light fallingupon the photo-electric cell H0. Because of the linear amplifyingcharacteristics of the thermionic tube, the current that flows throughthe coil of the relay 525 and the winding of the recording meter 526 islikewise directly proportional to the readings of the relative humidity.

A spring 524 having an adjustment nut is adapted to bias the armature ofthe relay downwardly and thus oppose the magnetic force of the coil ofthe relay. The circuit connections for the contacts of the relay 525constitute a pole changer such that, when the magnetic pull of the coilis greater than the spring bias, the armature is in the raised positionand a current of one polarity is delivered from the supply source to thehumidifying equipment, and when the magnetic pull is less than thespring bias, the armature is in the lowered position and a current ofthe opposite polarity is delivered from the supply source to thehumidifying equipment. When the armature of the relay is balanced, nocurrent is delivered to the humidifying equipment. Inasmuch as thehumidi'fying equipment constitutes 'no part of my invention, I haveomitted making a showing thereof. Briefly, the operation of thehumidifying equipment may be such that, when a current of one polarityis delivered thereto, the humidifying equipment responds to increase themoisture content of the surrounding air, and when no current or when acurrent of the opposite polarity is delivered thereto, the humidifyinlequipment responds to deliver no moisture content to the surroundingair. adjusting the tension ofthe spring'52l, the humidifying equipmentmay be so regulated as to maintain the relative humidity of thesurrounding air at a predetermined selected value. Also, there will bedescribedon the paper of the recording meter 526 a graph of the relativehumidity readings.

In Fig. 14, I show a modified form of a relative humiditycontrolcircuit, in which. power gridglow tubes I5| and 350 are employedto pass sufficient current to actuate a relatively large electromagnet525 that may be mechanically connected to an operating valve 53| of thehumidifying equipment. This circuit is substantially the same as thecontrol circuit shown in Fig. 35 of my pending application for LettersPatent, Serial No. 806,837, flied April 22, 1932, entitled Meets Thismeans that, by

ber 0| of the electrical meter is. As illustrated, a relatively strongspring 535 having an adjustment nut 529 is adapted to oppose themagnetic force of the electromagnet 528. As is apparent. this modifiedform of humidity control is very sensitive and, accordingly, themodulations or the variations from a normal or predetermined relativehumidity for any and all possible combinations of dry and wettemperature readings, as well as for so regulating the humidifyingequipment of an air conditioning system that the relative humidity ofthe surrounding air is maintained at a predetermined selected value.

As illustrated, the inner end of the wet bulb temperature hand 500passes through a suitable arcuate-aperture 52| in the dial or face 509and is connected to the rim of a gear wheel 5|5, which is rotatively andfreely mounted upon the tubular shaft 5|0 immediately in rear of thedial or face 509. The gear wheel 5|! meshes with a gear wheel 520 thatis mounted on the right end of the wet bulb shaft 50|-.' The gear wheels5|! and 520 have the same diameters and, accordingly, any angulardisplacement of the wet bulb shaft 50| is directly transmitted to thewet bulb temperature hand 508.

As hereinbefore mentioned that part of the psychrometric device formeasuring the effective temperature is based upon the reorganizedpsychrometric chart of Fig. 4. In view of the fact that several ways maybe employed to measure the effective temperature, as based upon thechart in Fig. 4, I do not intend to be limited by the illustratedembodiment. In carrying out my invention, the principal object is tosubtract 9. value (subtrahend) from the reading of the dry bulbtemperature (minuend) such that the remainder equals the effectivetemperature. With reference to Figs. 7 and 9, I propose to perform thissubtraction by utilizing the combination of a slidably mounted collar555 having a cam 550 mounted thereon which engages a pin 552 that iscarried by a second collar I to which the inner end of the eifectivetemperature hand 50! is connected. As illustrated, the inner end of thee!!- fective temperature hand 501 passes through the arcuate aperture52| in the dial or face 505 and thence through a suitably providedaperture in the web of the gear wheel M0 to thepoint where it isconnected to the collar 55L 'As shown in Fig. 9, a part of the tubularshaft 5! is slotted where the collar 555 is keyed by means of the key555, or other suitable means, to the dry bulb temperature shaft 500. Inthis manner, the collar 555 may move axially but is constrained to moveangularly with the dry bulb temperature shaft 500. Therefore, by axiallymoving the slidably mounted collar 555 to the right, the cam 550 engagesthe pm 552 and rotates the collar 55| that carries the eflectivetemperature band 551 backwards so that the eflective temperature handreads a value less than the dry bulb temperature hand 505 by an amountequal to the subtra-hend. In other words, the axial displacement of thecollar 555 and, consequently, the backward rotation of the collar 55|corresponds to the subtra-hend (a values, as marked off on the line OXof Fig. 4. Therefore, it remains to show how the axial displacement ofthe collar 555 is governed by the combination of the dry bulbtemperature, the differential temperature, and the air velocity. To thisend, I provide a slotted arm 552, in which the upper end of a pin 551that is connected to the collar 555 is disposed to slide when the drybulb temperature shaft 500 is rotated between the dry bulb temperaturereadings of 46 and 120. The lower end of the slotted arm 552 ispivotally connected at a pivot-point 510 to a slidably mounted member548 that is actuated in accordance with the air velocity, and the upperend of the slotted arm 552 is actuated by a slide bar 553 that isgoverned in accordance with the differential temperature.

The slide bar 553 is carried by a suitable bracket 551 and the left endthereof is adapted to engage a cam 542 that is suitably mounted upon theperiphery of a disc 541 which may be keyed, or otherwise connected, tothe tubular shaft 5"). The shape of the cam 542 is based upon the graphin Fig. 5, which represents the relationship between the linear units,as marked off on the differential temperature scale CD of Fig. 4 and thecorresponding differential temperatures. Therefore, the upper end of theslotted arm 552 is actuated in accordance with the differentialtemperature. In the position as shown, the differ ential temperature is18.

The lower end of the slotted bar 552 is actuated in accordance with theair velocity. The reference character 543 represents a shaft that isadapted to be rotated by an anemometer (not shown). For this particularapplication, the anemometer may be of the vane type, wherein theposition of the vane is determined by the force or velocity of the air.No showing of the anemometer is included in the drawings because itconstitutes no part of my invention. The end of the anemometer shaft 543is provided with a worm 545 which engages a worm wheel 545 that rotatesa polar cam 541, all of which is carried by a suitable support 544.Extending outwardly at an angle equal to the angle that the line EFmakes with the line OX of Fig. 4 is a bracket 550 having upwardlyextending spaced ears in which the member 548 is slidably mounted. Thelower end of the slidably mounted member 548 engages the periphery ofthe polar cam 541. A spring 549 disposed between the upwardly extendingspaced ears and surrounding the member 548 is adapted to big the lowerend of the member 548 against the polar cam 541. The shape of the polarcam 541 is based upon the polar graph in Fig. 6, which represents thepolar relationship between the linear units, as marked off on the lineEF of Fig. 4, and the corresponding air velocities. Therefore, theslidably mounted member 548 may be moved in-and-out by the rotation ofthe anemometer shaft 543 so that the position of the pivot-point 51!)corresponds to the air velocity values, as marked off on the line EF ofFig. 4. In the position as shown, the arm 552 DB) intersects the arcuateline 541 (Fig. 3) or the circumference of the disc 541 (Fig. '7), andthe arcuate position of the slide rod 553 relative to the pivot-point510 is determined by the insertion of the radius line'T (correspondingto 120 DB) with the arcuate line 541 (Fig. 3) or the circumference ofthe disc 54I (Fig. 7). In theposition, as indicated, the pivot-point 510therefore represents a dry bulb temperature of 46 and the position ofthe slide rod 553 always represents a dry bulb temperature of 120. Thepin 551 is positioned at a dry bulb temperature of 90 by shaft 500 andcollar 555. Also the in tersection of the radius lines V (ordifferential) and W (or 35 differential) with the arcuate line 541 (Fig.3) or the circumference of the disc 541 (Fig. '1) determines the arcuatelength of the cam 542. In the position as shown, the disc 5 has beenrotated by the shaft 510 in a clockwise direction to the point where adifferential temperature of 18 onthe cam 542 coincides with the engagingend of the slide rod 553. Therefore, the slidably mounted collar 555 isaxially actuated to the right to such a position that the cam 560, incombination with the pin 562 and the collar 56l, retracts the effectivehand 501 an angular distance equal to This means that with a dry bulbtemperature of 90 and a wet bulb temperature of 72 (a difference of 18)the effective temperature is 80, or 10 less than the dry bulbtemperature reading.

Depending from the collar 551 is an effective temperature graph-member564. The light transmitting portion of the effective temperaturegraph-member 564 has an arcuate base line with effective temperaturereadings ranging from 46 to 120 and to every value of the temperaturereading there corresponds an ordinate of equal value. In the position asshown in Fig. 10, the plane of light is represented by the dotted lineand it is passing through the light transmitting portion at an effectivetemperature reading of 80. A spring 566 is connected to this graphmemberin order to bias the effective hand in a clockwise direction, thuscausing the pin 562 to yieldingly engage the edge of the cam 560. Thiscauses a longitudinal force to be exerted upon the slidably mountedcollar 555, with the result that the slide rod 553 is likewiseyieldingly constrained against the cam 542.

As is'apparent, by means of the effective temperature graph-member 564,in combination with a photo-electric cell and suitable amplifying cir--cult and an appropriate relay for regulating the control currentdelivered to the air conditioning equipment, the condition of the air ina building may be maintained at a predetermined selected effectivetemperature.

In theatres and department stores, which are cooled artificially in warmweather, the contrast between the outdoor and indoor air conditions,becomes the deciding factor in regard to the most desirable effectivetemperature to be maintained in the inside of the building. The objectof cooling theatres in the summer is not to reduce the effectivetemperature to the optimum value, but to maintain therein a reasonablycomfortable effective temperature and at the same time to avoidsensations of chill or of intense heat in entering and leaving thebuilding. The relationship between desirable indoor effectivetemperature in summer corresponding to various outdoor effectivetemperatures is plotted in Fig. 12. The effective temperature values forthe curve in Fig. 12 are listed in the chart immediately below thefigure. All of these values listed in the chart, except those for theoutside effective temperatures, were taken from a table appearing onpage 82 of the 1931 edition of the American Society and Heating andVentilating Engineers Guide. The values appearing in the outsideeffective tem-' perature column were taken from the psychrometric chartin Fig. 1, using the corresponding outside dry and wet bulb temperatureswith the same number of grains of moisture per pound of dry air. It isnoted that the effective temperature values for the curve in Fig. 12substantially define a straight line and for all practical purposes-.,it may be considered as such, and that the higher the effectivetemperature on the outside, the higher the corresponding effectivetemperature on the inside. Therefore, from the foregoing, we

observe that the control circuits which regulate the air conditioningequipment must be such as to respond to both the outside and insideeffective temperatures. Such a control circuit is shown in Fig. 11. Ingeneral, this control circuit comprises two independent amplifyingcircuits, which differentially act to operate a relay for reversing thepolarity of the current delivered from the supply source to the controlapparatus of the air conditioning equipment. This means that at leasttwo psycnrometric devices must be utilized; one placed on the outside ofthe building and the other located on the inside of the building. Theupper amplifying circuit is responsive to the outside effectivetemperatures and the plate current that flows through the coil 58!] isdisposed to exert a force that opposes the force set up by the platecurrent that flows through the coil 582,which is responsive to theinside effective temperatures. The spring 585 having an adjustment nutis likewise arranged to oppose the magnetic force of the coil 582. Asillustrated, an adjustable resistor SM is connected in shunt with thecoil 58!], so that the magnetic force of the coil 580 is relatively weakas compared to the magnetic force of the coil 582. The relativevalues'of the magnetic force of the coils 580 and 582,

together with the spring force, are such that, for example, with anoutside effective temperature of 68.2 and with an inside effectivetemperature of 67 the armature of the relay is balanced and the airconditioning equipment is inoperative. However, should the outsideeffective temperature rise, the balanced condition of the relay isdisturbed, because the amplifying circuit that is responsive to theoutside air conditions passes more current to increase the magnetic pullof the coil 580. This causes the air conditioning equipment to responduntil the inside effective temperature is raised to a point where thearmature of the relay again becomes balanced. In other words a change inthe outside effective temperature causes such a change in the insideeffective temperature that the relationship conforms substantially withthe curve shown in Fig. 12, or with any other desirable relationshipwhich gives the most comfortable feeling.

As illustrated, a recording meter 583 and a recording meter 584 may beemployed to record the outside. and inside effective temperaturesreadings, respectively.

In Fig. 15, I show a fragmentary view of a modified form of theeffective temperature control circuits, in which two power grid-glowtube circults, such as the one illustrated in Fig. 14, may be employedto operate a valve 592, or other control means of the air conditioningequipment, by

means of two electro-magnets 590 and 5M direct- 1y connected thereto,which are energized by the power grid-glow tubes. Also two recordingmeters 593 and 594 may be utilized to record, respectively, the outsideand inside effective temperatures.

As shown in Fig. 15, the valve 582 may, for example, control the flow ofa heating medium in a pipe 602 leading to a conventional radiator (notshown). Hot water or steam may be supplied to the valve from a heatingplant 600 provided with the usual riser pipe GUI and return pipe 603.

In Fig. 16 I have shown a conventional conditioning apparatus which maybe controlled by means of a control system of the type shown in Fig. 11.Reference numeral SIB designates a conventional heating plant which isadapted to supply a heating medium such as steam or hot water to theusual form of radiator 6I5. A solenoid valve 6 is shown in the riserpipe M3 for controlling the flow of the heating medium through theradiator SIS. The solenoid valve 6 is controlled by a magnetically'operated switch of the type shown in Fig. 11.

Inasmuch as the effective temperature is a measure of any and allpossible combination of the dry bulb temperature, the relative humidity,and the air velocity, the effective temperature control circuits ofFigs. 11 and 15 may regulate any one of the three factors while theother two may be allowed to vary uncontrolled. For example if thecontrol circuits of Figs. 11 and 15 are arranged to regulate the drybulb temperature only, the relative humidity and the air velocity mayvary uncontrolled, because the dry bulb temperature remains at the samepredetermined selected value. In other'words, my effective temperaturecontrol system is such that, for any change in the relative humidity orthe air velocity which results in a change in the effective temperature.the dry bulb temperature is corrected to off-set the said change in theeffective temperature caused by the change in the relative humidity andthe air velocity. Therefore, even though the relative humidity and theair velocity may vary uncontrolled, the effective temperature ismaintained at a predetermined selected value. In those cases where theair velocity is held constant, it is not necessary to use an anemometer,but the positionof the slidably mountedmember 548 may be adjustably set,by a set screw or other suitable means, at values that correspond to thepredetermined selected constant air velocity.

It is to be pointed out that the amplifying circuits used through myinvention are merely illustrative and, accordingly, they may take otherforms. In the illustrated forms, the constancy or calibration of thecircuits remain very accurate over a reasonable length of time, which isusually at least a year or more-and this condition will improve with themanufacture of bet ter tubes. However, should the operating conditionsrequire that no change in the calibration take place over a period ofseveral years, a uni method may be employed, which counterbalances anychange in the calibration.

Since certain changes in my invention may be made without departing fromthe spirit and scope thereof, it is intended that all matters containedin the foregoing description and shown inbased upon the dry-bulbtemperature and the dry-bulb temperature, the wet-bulb temperature, andthe air motion comprising, in combination, means controllable inaccordance with the dry bulb temperature, means controllable inaccordance with the wet bulb temperature, means controllable inaccordance with the air motion, differential means governed by the drybulb temperature means and the wet bulb temperature means, and meansgoverned by the dry bulb,

temperature means, the differential means, and

the air motion means for giving the measure- I ment of the efiectivetemperature.

2. A measuring device for giving a measureture comprising, incombination, means controllable in accordance with the dry-bulbtemperature, means controllable in accordance with the wet-bulbtemperature, differential means governed by the dry-bulb temperaturemeans and the wet-bulb temperature means, a relative humidity scale, anda relative humidity member disposed to move along the relative humidityscale and actuated by the dry-bulb temperature means and thedifferential means for giving the measurement of the relative humidity.

3. A measuring device for giving a measurement of the relative humiditybased upon the dry-bulb temperature and the wet-bulb temperaturecomprising, in combination, means rotatable in accordance with thedry-bulb temperature, means rotatable in accordance with the wet-bulbtemperature, 'difierential means rotatable by the dry-bulb temperaturemeans and the wet-bulb temperature means, a relative humidity scale, anda relative humidity indicating hand disposed to move along the relativehumidity scale and actuated by the rotational movements of the dry-bulbtemperature means and the differential means.

4. A measuring device for giving a measurement of the efiectivetemperature under conditions of substantially constant air motion and ameasurement of the relative humidity both measurements of which beingbased upon the drybulb temperature and the wet-bulb temperaturecomprising, in combination, means controllable in accordance with thedry-bulb temperature, means controllable in accordance with the wetbulbtemperature and two separate means governed respectively by both of thetwo foregoing means, one of said separate means having graduations andactuating connection to give the measurement of the effectivetemperature under conditions of substantially constant air motion andthe other separate means being adapted to give the measurement of therelative humidity.

5. A measuring device for measuring the relative humidity and theefiective temperature in all combinations of the dry-bulb temperature,the wet-bulb temperature, and the air motion comprising, in combination,means controllable in accordance with the dry-bulb temperature, meanscontrollable in accordance with the wetbulb temperature, meanscontrollable in accordance with the air motion, diflerential meansgoverned by the dry-bulb temperature means and the wet-bulb temperaturemeans, means governed by the dry-bulb temperature means and thedifierential means for measuring the relative.

humidity, and means governed by the combination of the dry-bulbtemperature means, the differential means, and the air motion means formeasuring the effective temperature.

6. A device for. giving a measurement that is moisture comprising, incombination, means for giving a measurement of the dry-bulb temperature,means responsive to the moisture and the dry-bulb temperature for givinga subtra-hend value, and means for subtracting the subtrahend value fromthe measurement of the drybulb temperature to give the said measurement.

7. A device for giving a measurement of the effective temperature incombinations of air mo- 10 tion and temperature, which measurement is anindex of the thermo-equivalent condition of the body under conditionshaving a substantially constant relative humidity comprising meansindependent of the temperature and influenced by the air motion andmeans influenced by the temperature and means influenced by both of saidmeans for giving the said measurement.

8. A device for giving a measurement of the effective temperature incombinations of air motion and temperature, which measurement is anindex of the thermo-equivalent condition of the body under conditionshaving a substantially constant relative humidity comprising, incombination, means for giving a measurement; of the dry-bulbtemperature, means'independent of temperature and responsive to the airmotion for giving a subtra-hend value, and means for subtracting thesubtra-hend value from .the measurement of the dry-bulb temperature togive the said measurement.

9. A device for giving a measurement of the effective temperature incombinations of air motion and temperature, which measurement is, anindex of the thermo-equivalent condition of the body under conditionshaving a substantiallyconstant relative humidity comprising,incombination, means influenced by the dry-bulb temperature, meansindependent of temperature and influenced by the air motion, and meansreceiv- 0 ing motion from each of said foregoing means and resolvingsaid motion into a resultant movement of its own for giving the saidmeasurement.

10. A device for giving a measurement based upon air motion, moisture,andtemperature comprising means independent of temperature andinfluenced by the air motion, means influenced by the moisture, andmeans influenced by the temperature for giving the said measurement, andconnections between said means such that the rate at which the airmotion influences the said measurement is greater at lower temperaturesthan at higher temperatures and that the rate at which the moistureinfluences the said measurement is greater at higher temperatures thanat lower temperatures.

11. A measuring device for indicating the sensation of temperaturecondition produced upon a person by relative condition of the air basedupon the combination of the dry bulb tempera 0 ture, the moisturecontent, and the motion thereof, comprising, in combination, meansinfluenced by the dry bulb temperature, means influenced by the moisturecontent, means controllable in accordance with the air motion, and meansgoverned by the three foregoing means for giving said indication.

12. A device for giving a measurement that is based upon both themoisture and the dry bulb temperature comprising, in combination, meansresponsive to the moisture, means responsive to the dry bulbtemperature, connecting means including a movable member connected toand actuated by the two foregoing means for giving the said measurement.and said connecting means in- 7 eluding means for causing the moisturemeans to affect the movable member with a greater movement only as thedry bulb temperature increases above the temperature at which a changein moisture has no influence on the effective temperature.

13. A device for giving a measurement that is based upon both themoisture and the dry bulb temperature comprising, in combination, meansresponsive to the dry bulb temperature, means responsive to themoisture, connecting means receiving motion from each of said foregoingmeans and resolving said motion into a resultant movement of its own forgiving the said measurement, and means for causing the moisture means toproduce substantially no part of said resultant movement at apredetermined low temperature.

14. A measuring device for giving a measurement of the effectivetemperature in combinations of moisture and temperature, whichmeasurement is an index of the thermo-equivalent condition of the bodyunder conditions of substantially constant air motion comprising, incombination, means controllable in accordance with the dry bulbtemperature, means controllable in accordance with the moisture, a drybulb temperature indicating member controlled by the dry bulbtemperature means, an effective temperature indicating member controlledby the dry bulb temperature means and the moisture means, graduations toindicate the measurement of the dry bulb temperature and the effectivetemperature, said graduations being sealed off on substantially the sameproportionate basis and calibrated with the same temperature readings,and means for causing the moisture means to make the effectivetemperature member read less than the dry bulb temperature member.

15. A measuring device for giving a measurement of the effectivetemperature in combinations of moisture and temperature, whichmeasurement is an index of the thermo-equivalent condition of the bodyunder conditions of substantially constant air motion comprising, incombination, graduations to indicate the measurement of the dry bulbtemperature and the effective temperature, said graduations beingcalibrated with the same temperature readings, means controllable inaccordance with the dry bulb temperature to indicate the dry bulbtemperature reading, means carried by the dry bulb temperature means toindicate the effective temperature reading, means controllable inaccordance with the moisture, means for causing the dry bulb temperaturemeans and the moisture means to actuate the effective temperatureindicating means. and means for causing the moisture means to make theeffective temperature indicating means to read less than the dry bulbtemperature means.

16. A measuring device for giving a measurement of the effectivetemperature in combinations of moisture and temperature, whichmeasurement is an index of the thermo-equivalent condition of the bodyunder conditions of substantially constant air motion comprising, incombination, a common scale to indicate the measurement of the dry bulbtemperature and 'the effective temperature,means controllable inaccordance with the dry bulb temperature to indicate the dry bulbtemperature reading, means to indicate the effective temperaturereading, means controllable in accordance with the moisture, means forcausing the dry bulb temperature means and the moisture means to actuatethe effective temperature indicating means, and means for causing themoisture means to make the ef fective temperature indicating means toread less than the dry bulb temperature means.

17. A measuring device for giving a measurement of the effectivetemperature in combinations of moisture and temperature, whichmeasurement is an index of the thermo-equivalent condition of the bodyunder conditions of substantially constant air motion comprising, incombination, a member movable about an axis to measure the dry bulbtemperature, a member movable about the same axis to measure theeffective temperature, means controllable in accordance with themoisture, and means for causing the dry bulb temperature member and themoisture means to actuate the effective temperature member.

18. A device for giving a measurement of the effective temperature incombinations of moisture and temperature which measurement is an indexof the thermo-equivalent condition of the body under condition ofsubstantially constant air motion comprising, in combination, meansinfluenced by the dry bulb temperature, means influenced by themoisture, a movable member for giving a measurement of the effectivetemperature in combinations of moisture and temperatures, means governedby the dry bulb temperature means and the moisture means for actuatingthe effective temperature member, means.

for causing the dry bulb temperature means to produce a relatively largepart of the movement of the effective temperature member, and means forcausing the moisture means for producing a relatively small part of themovement of the effective temperature member.

19. A device for giving a measurement of the effective temperature incombinations of moisture and temperature which measurement is an indexof the thermo-equivalent condition of the body under condition ofsubstantially constant air motion comprising, in combination, meansinfluenced by the dry bulb temperature, means influenced by themoisture, a movable member for giving a measurement of the effectivetemperature in combinations of moisture and temperatures, means governedby the dry bulb temperature means and the moisture means for actuatingthe effective temperature member, means for causing the dry bulbtemperature means to produce a relatively large part of the movement ofthe effective temperature member, means for causing the moisture meansfor producing a relatively small part of the movement of the effectivetemperature member, and means for causing the dry bulb temperature meansto reduce the influence that the moisture means has upon the movement ofthe effective temperature member as the dry bulb temperature decreases.

20. A device for giving a measurement of the efiective temperature incombinations of air motion and temperature which measurement is an indexof the thermo-equivalent condition of the body under conditions having asubstantially constant relative humidity comprising, in combination,means influenced by the dry bulb temperature, means independent of thetemperature and influenced by the air motion, a movable member forgiving the measurement of the effective temperatures in combinations ofair motion and temperature, means governed by the dry bulb temperaturemeans and the air motion means for actuating the effective temperaturemember,

and means for causing the air motion means to produce a relatively smallpart of the movement of the effective temperature member.

21. A device giving a measurement of the effective temperature incombinations of air motion and temperature which measurement is an indexof the thermo-equivalent condition of the body ,under conditions havinga substantially. constant relative humidity comprising, in combination,means influenced by thedry bulb temperature, means independent of thetemperature and influenced by the air motion, a movable member forgiving the measurement of the effective temperatures in combinations ofair motion and temperature, means governed by the dry bulb temperaturemember, means for causing the dry bulb temperature means to produce arelatively large part of the movement of the efl'ective temperaturemember, means for causing the air motion means to produce a relativelysmall part of the movement of the effective temperature member, andmeans for causing the dry bulb temperature means to increase theinfluence that the air motion means has upon the movement of theeffective temperature member as the dry bulb temperature decreases.

22. A device for giving a measurement of the efiective temperature incombinations of moisture and air motions, which measurement is an indexof the thermo-equivalent condition of the body under conditions having asubstantially constant dry bulb temperature comprising, in combination,means influenced by the moisture, means independent of the temperatureand influenced by the air motion, and means influenced by both of saidmeans for giving the said measurement of the effective temperature.

23. A device for giving a measurement of the effective temperature incombinations of moisture and air motions, which measurement is an indexof the thermo-equivalent condition of the body under" conditions havinga substantially constant dry bulb temperature comprising, incombination, means influenced by the moisture, means independent of thetemperature and influenced by the air motion, and means receiving motionfrom each of said foregoing means and resolving said motion into aresultant movement of its own for giving the said measurement of theeffective temperature.

24. In an apparatus of the class described, in combination, meansmovable to give a measurement of dry bulb temperature, means movable togive a measurement of the relative humidity,

rneans movable in accordance with the eflective temperature incombinations of moisture and temperature under conditions ofsubstantially constant air motion, means for causing relative movementbetween the effective temperature means, the relative humidity means andthe dry bulb temperaturemeans, and means for .opposing the mdyement ofthe effective temperature means to transmit movement back to either thedry bulb temperature means or the relative humidity means.

25. In an apparatus of the class described, in combination, meansmovable to give a measurement of the relative humidity, means movable togive a measurement of the air motion, means movable in accordance withthe efiective temperature, in combinations of moisture and air motionunder conditions having a substantially constant dry bulb temperature,means for causing relative movement between the effective temperaturemeans, the relative humidity means and the air motion means, and meansfor opposing the movement of the effective temperature means to transmitmovement back to either the relative humidity means of the air motionmeans.

26. In an apparatus of the class described, in combination, meansmovable to give a measurement of the dry bulb temperature, means movableto give a measurement of the air motion, means movable in accordancewith the eifective temperature in combinations of dry bulb temperatureand air motion under conditions having a substantially constant relativehumidity, means for causing relative movement between the effectivetemperature means, the dry bulb temperature means and the air motionmeans, and means for opposing the movement of the efiective temperaturemeans to transmit movement back to either the dry bulb temperature meansor the air motion means.

27. A device for giving measurement that is based upon both the moistureand the dry bulb temperature comprising, in combination, a movablemember, means influenced by the moisture for moving the movable member,a second movable member, means for interconnecting the first and thesecond movable members, means responsive to the dry bulb temperature forvarying the interconnecting means to modify the extent of the movementof the second movable member relative to the movement of the firstmovable member, a third movable member for giving the said measurement,and means responsive to the movement of the second movable member andthe dry bulb temperature for actuating the third movable member to givesaid measurement.

28. A device for giving a measurement of the effective temperature in aspace having a sub-. stantially constant air velocity comprising incombination, means influenced by the moisture, means influenced by thedry bulb temperature, a movable member actuated by the two foregoingmeans for giving the said measurement, and compensating means wherebysaid measurement is based on the particular air velocity within thespace.

29. A measuring device for giving a measurement of the efiectivetemperature in combinations of moisture and temperature, whichmeasurement is an index of the thermoequivalent condition of the bodyunder conditions of substantially constant air motion comprising, incombination, a member movable about an axis to measure the dry bulbtemperature, a member movable about an axis to measure the effectivetemperature, means controllable in accordance with the moisture, meansfor causing the dry bulb temperature member and the moisture means toactuate the effective temperature member, and compensating means wherebysaid device may be adjusted to give measurements based on the particularair motion conditions.

30. A device for giving a measurement of the efiective temperature,comprising in combination/means influenced by the dry bulb temperaturecondition, means influenced by the moisture condition, meanscontrollable in accordance with the air motion condition, mechanismgoverned by the three foregoing means for giving said measurement, andmeans whereby one of said means may be adjustably set at values thatcorrespond to predetermined constant conditions.

31. In combination, flrst means controllable in accordance with a firstfunction of the psychrometric condition of air, second meanscontrollable in accordance with a second function of the psychrometriccondition of air, third means controllable in accordance with a thirdfunction of the psychrometric condition of air, differential meansgoverned by the first and second means, and means governed by said firstmeans, the differential means and the third means.

32. In combination, first means for giving a measurement of a firstfunction of the psychrometric condition of air, second means responsiveto a second-function of the psychrometrio condition of air and the firstfunction of the psychrometric condition of air for giving a subtra-hendvalue, and means for subtracting the subtrahend value from themeasurement of the first means.

33. In combination, a first temperature responsive means, a secondtemperature responsive means, means actuated by said first and secondnamed means, and means controllable in accordance with air motion formodifying the action of one of said temperature responsive means.

34. In combination, a first means responsive to one function of thepsychrometric condition

